Add missing include

[bernhardmgruber]

The Split mapping depends on a functionality from View.hpp. Not having the include made the amalgamated header not work.

[codecov]

Codecov Report

Merging #486 (adba548) into develop (a4a9f14) will not change coverage.
The diff coverage is n/a.

❗ Current head adba548 differs from pull request most recent head 0f152d0. Consider uploading reports for the commit 0f152d0 to get more accurate results

@@           Coverage Diff            @@
##           develop     #486   +/-   ##
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  Coverage    99.23%   99.23%           
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  Files           59       59           
  Lines         5392     5392           
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  Hits          5351     5351           
  Misses          41       41